For several weeks, inspired by onetuberadio's messages, I've been looking into the feasibility of making vacuum tubes. The technical challenges overcome by our parents in production of vacuum tubes were significant, and it is to their credit they created entire industries around them.

To my surprise, it appears that vacuum tube research has continued past the end of the "vacuum tube age". The link below reports on NASA research into a vacuum tube technology that eliminates the need for a heater and thus provides a dramatic reduction in energy consumption. Plus! The technology employs helium inside the envelope to reduce strain on the envelope. Plus! The resulting gates are (apparently) capable of operating at speeds greater than can be achieved by existing solid state devices.